The Seamstress image manipulation library promises smaller images without compromising detail. Version 1.0.0 of the software, which was released recently, uses an "energy function" to analyze various areas of the image before compressing and does not change eye-catching areas.

Content-aware image scaling is how the inventors Ariel Shamir (Interdisciplinary Center Herzliya) and Shai Avidan (Mitsubishi Electric Research Laboratories) refer to their method, which only modifies the "boring" parts of a graphic. The GPL'd Seamstress C library implements the approach shown in the figure: when the original image (top) is resized, the marbles simply move closer together without changing shape (bottom left). The version bottom right shows a conventionally scaled version that clearly demonstrates the differences.

Compressed: Seamstress simply compresses the free areas between the marbles (bottom left). In contrast to a simple width rescale (bottom right) the marbles keep their shape.

Besides the library, the Sourceforge project includes the GTK application Arachne, which demonstrates the functionality of Seamstress without requiring programming skills on the part of the user. The application modifies Tiff images dynamically to reflect the window size. Besides automatic analysis of the screen area by the software, users can manually select objects they do not wish to scale. As the screenshots show, you can even remove undesirable elements from images without compromising the realistic character of the image.

(Peter Kreußel)

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